1. Field of the Invention
The present invention relates to combustion control system. In particular, the present invention relates to a dynamic feed forward system for controlling flow of air supplied to a burner to maximize combustion efficiency.
2. Description of Prior Art
The need for maximizing combustion efficiency in all types of combustion firing operations is of major importance. The waste of energy through inefficient combustion can no longer be tolerated in view of high costs and limited quantities of fossil fuel.
In a typical fuel combustion system, there is a certain amount of air required for efficient and complete combustion. If this amount is too little, combustion will be incomplete. The unburned fuel results in loss of efficiency, smoke emission, and possible creation of an explosive mixture. Too much air increases the total mass flow through the system and thus increases the amount of heat lost in the flue gas.
To avoid the problems which result when too little air is supplied, combustion systems are typically set on the "safe" side with a high percentage of excess air (in excess of the stoichiometric amount of air required for complete combustion) entering the system. The cost of heating this additional excess air, however, is significant. Any additional air above the minimum required value increases total mass flow through the system and carries away unused heat. The additional excess air also reduces flame temperatures in the boiler or burner and results in less heat absorption in the furnace and higher stack temperatures.
There is a continuing need for a combustion control system which will operate a particular combustion system so that the combustion system fires with a minimum of excess air over a wide firing range. The combustion control system should be capable of operation with a wide variety of combustion equipment, and should be capable of use not only in new systems, but in retrofit control systems.
In the past, although some specialized combustion control systems have been developed for particular combustion equipment, there has remained a need for a highly flexible combustion control system which is useable with a wide variety of different combustion equipment.